Knitting machine



United States Patent 3,253,429 KNITTING MACHINE Maxwell P. Dodds, Laconia, and Kenneth W. Newlen,

Gilford, N.H., assignors to Scott 8: Williams, Incorporated, Laconia, N.H., a corporation of Massachusetts Filed Feb. 7, 1963, Ser. No. 256,884 3 Claims. (Cl. 66-149) This invention relates to knitting machines and has particular reference to grab takeups of the type adapted to seize the end of a stocking and maintain it under tension during knitting.

Takeups of the type mentioned are widely used in circular knitting machines, and reference may be made to Lawson Patent 2,709,352, dated May 31, 1955, for a takeup of this type which is commonly used. As applied to a circular rotating cylinder knitting machine, this involves the provision of a cup and clamp combination which is raised to the upper end of a needle cylinder during the knitting of a turned welt, the clamp being opened so that the cup may receive the turned welt of a stocking as it is being knit, the welt being entered into the cup by a blast of air. When the welt is completed and transfer is. made, the clamp closes on the welt and as knitting proceeds further the cup and clamp fall under the action of gravity maintaining tension on the stocking as is desirable to secure the proper formation of stitches. When the stocking is completed and the fabric is pressed off the needles, the clamping assembly reaches the lower end of its travel and the clamp is released and the completed stocking is blown from the machine.

The mechanism is rather complex mechanically, but has a further disadvantage which the present invention overcomes. Because of the length of a ladys stocking, and because of the necessary mechanical construction 'of the clamp assembly, an objectionable vertical height is required between the level of the knitting machine needles and the floor on which the machine rests. Accordingly, in these machines it has generally been necessary to adopt a construction raising the level of the needles abnormally above the floor with the attendant requirement of providing a platform on which the operator must stand above the floor level in order to observe the knitting instrumentalities.

One of the objects of the present invention is to provide a grab takeup device which minimizes the vertical height requirements of the machine.

Additionally, in accordance with the invention, the mechanism required is greatly simplified and except for devices having simple mechanical movements and construction the operation is primarily pneumatic in character. Pneumatic operation of a grab takeup has been proposed, as exemplified by the patent to Tew 2,729,082, dated January 3, 1956. However, the device of this patent is also complex and not completely reliable. A further object of the invention relates to the achievement of pneumatic operation in very simple and reliable fashion.

In brief, the present invention involves the provision of a grab assembly including a piston-like arrangement which is moved into grabbing position by air-pressure.

In this position the air-pressure holds the takeup open to receive the welt of a stocking during the knitting of the welt. When the welt is completed, and transfer is made, a decrease of air pressure effects clamping of the stocking wel-t and then the pressure may be cut off so that the takeup tensions the stocking during the knitting of other parts thereof. When the knitting of the stocking is completed, and the fabric is cast off the needles, the take-up, with the. stocking, drops to the bottom of its mounting tube and is latched at this position. tion of air pressure then opens the clamping arrangement and the stocking may be blown out of the tube.

The further applica- One of the further objects of the invention relates to the provision of an arrangement by which, consistently with the application of air pressure to hold the clamping assembly raised and opened, air flow is properly permitted to cause the welt to enter the clamping assembly to be engaged thereby.

The foregoing and other objects of the invention will become more apparent from the following description, read in conjunction with the accompanying drawing, in which:

FIGURE 1 is a vertical section showing the parts of a knitting machine in the vicinity of the needle cylinder, and in particular showing the upper end of a tube mounting the grabbing assembly, the assembly being shown in full lines in the position occupied just prior to opening of its clamp, the position of the open clamp being indicated in construction lines;

FIGURE 2 is a similar section but showing the lower end of the guiding tube with the clamping assembly in the position it occupies at the lower end of the tube prior to release of a stocking; and

FIGURE 3 is a transverse section taken on the plane indicated at 3-3 in FIGURE 2.

While the invention is obviously applicable to a stationary cylinder circular machine, it is shown as applied to a rotary cylinder machine. It will be understood that the machine is generally conventional, and accordingly only so much of the machine is illustrated as is involved in the operation of the takeup. Among the conventional parts are the needle cylinder 2 which mounts the needles 4 operable in conventional fashion by the usual cams. The sinker dial 6 supports sinkers 8 which are controlled by conventional cams in the sinker cap 10. The dial 12 supports the elements 14 arranged to hold stitches for the'forrnation of the usual turned welt. The driving sleeve gear is shown at 16, this, as usual, being splined to the needle cylinder to drive it but permit axial movements for control of stitch sizes. This gear is driven in the usual fashion to provide both rotation and reciprocation, the latter forthe formation of heels and toes of stockings. The machine is of the type in which a turned welt is first knit, starting on bare needles. When a stocking is finished by formation of the loopers rounds it is pressed off. Grab takeups of the type here involved are used to provide proper tensioning during knitting, since when stockings are individually produced and pressed off tension cannot he applied in the fashion used when string work is being done.

In accordance with the present invention, there is pro vided a thin walled tube 22 extending from the top of the sleeve gear downwardly to terminate in a closure member 24. As illustrated, thistube is stationary, though it may well be made in two parts, the upper part rotating, and the lower part stationary. It is found, how ever, that it is unnecessary to provide an upper rotating portion since free bearing mounting of the grabbing elements permits rotation of the stocking with the needle cylinder. The tube 22 is desirably metallic but may be provided with one or more plastic windows (not shown) through which the knitting progress may be viewed.

The closure member 24 is provided with an air inlet passage 26 tapped at 28 to provide connection to an air supply line. The tube is provided with an opening 30 through which a blast of air may be directed as hereinafter more fullydescribed to effect discharge of a completed stocking through an opposite opening 36 controlled by a rotary gate. In its upper portion there are spaced openings 44 located as will become clear hereafter for the flow of air used to locate the turned welt as it is being formed within the takeup. A hearing 46 mounts the upper end of the when in the sleeve gear. As shown, below the level of the openings 44 there is a clearance 48 between the sleeve gear and the tube 22.

Surrounding the portion of the tube 22 at the location of the openings 30 and 36 there is a rotary gate which is indicated generally at 50. This is provided with an opening 52 which corresponds in size and position to the opening 36. The gate is also provided with an opening at 61 provided with a nipple receiving a flexible tube 63 connected to the output passage of a valve 65 which controls flow of air under pressure from a supply line 67. The valve is of a type which is opened by depression of a stem.

The grab assembly comprises a clamp 60 having a flange 62 mounted by means of a ball bearing 66 for free rotation on a member 68 which has a loose mounting provided by a pin and slot arrangement indicated at 70 on the upper end of a stem 72. The clamp 60 is provided with a depending cylindrical portion surrounding the stem 72 to prevent entanglement of the welt of a stocking with the elements at the upper portion of the stem. The stem 72 is secured in a cylindrical piston 74 which has a close sliding fit in the tube 22. Complete sealing of the piston in the tube 22 is not required, but it is desirable to minimize the bypassing of the piston by air by close clearance, though the clearance is such as not to impede free fall of the piston. Openings 82 are provide-d in the piston wall for passage of air. A compression spring 84 having its lower end resting on the piston supports a collar 86 freely slidable on the spindle 72, this collar mounting a I ball bearing 88 supporting a cup 90 which at its upper end 92 is provided with an annular step coacting with the flange 62 of the clamp 60 to clamp stocking welts. The exterior of the cup has a diameter sufiiciently less than the interior diameter of the tube 22 to permit its free rotation. The cu 90 is also provided with openings 94 for the passage of air. It will be seen that the openings 82 and 94 provide cage like structures which permit free flow of air irrespective of their relative angular positions. A plastic bumper button 75 is secured at the bottom of the piston to cushion shock.

The top of the sleeve gear mounts an inwardly projecting stop 96 engageable by the upper edge of the cup 90 to limit its upward movement.

An air blast is provided through tube 98 and between elements 14 during welt knitting as hereafter described to locate the welt in the takeup.

Air is supplied to the passage 26 through a line 100 connected to the outlet port of a valve 102 of the supply and waste type. The conventional movable element of this valve operated by depression of a stem 106 is arranged to connect the line 100 alternatively with the air supply line 104 or with a vent to atmosphere. The stem 106 is operable from the main cam drum 1 14 of the machine through the action of cams 110 and 112 on this drum on a follower which, together with its connection is conventionalized as a rod 108. Actually this connection is desirably made by the use of a Bowden wire operated by a cam follower and acting through a lever upon the stem 106 of the valve 102. A similar arrangement (not shown) is provided for control of the valve 65 at the proper time.

The only other mechanical connection required is that for producing oscillation of the gate 50, this being provided by a Bowden wire 116 operable in usual fashion from cams on the main cam drum 114.

In addition to providing for porting, the ments control a latching arrangement in the inwardly projecting latch 118 pivoted to the and urged inwardly by a spring 122. This ranged to project inwardly into an annular slot .124 in the cup 90 when the openings 36 and 52 are aligned and the openings 30 and 61 are also aligned, the tube 22 being provided with an opening at 126 for this purpose. The latch is retracted by the cam action of this opening when the gate is moved from a position of alignment of the latch with the opening.

The operation of what has been described is as follows:

gate moveform of an gate at 120 latch is ar- The stocking is started in conventional fashion on bare needles, and initial loops are held on the elements 14 while knitting of the welt proceeds. During the initial portion of the knitting of this welt, the gate 50 is closed to prevent escape of air through the openings 30 and 36. When the gate is in such position, the latch 118 lies against the outer surface of the tube 22 beyond its opening 126, the edge of which cams the latch outwardly as the gate is moved to this position. Air is then applied from supply line 104 through valve 102 and connection 100 to the interior of the tube 122 below the piston 74. The piston and the assembly which it carries is thus forced upwardly through the tube 22. It has been found that because of the large transverse area presented by the piston special packing is unnecessary, a sliding fit in the tube 22 minimizing air leakage to an acceptable degree even as the piston passes the opening 36, the wall of the tube 22 being sufiiciently thin to prevent undue loss of air.

When the upper end of the cup engages the stop 96, the cup is arrested, but the piston continues to rise, compressing spring 84, and raising further the clamp 60 which ultimately engage the dial 12, though this engagement is not essential. All that is required is that the clamp should rise away from the upper edge of the cup to provide a clearance space for reception of the welt fabric as indicated at the upper left of FIGURE 1. The welt fabric is driven downwardly into the cup by the action of air flowing through the tube 98. However, for this action to occur properly, the air must have a free passage through and past the fabric to exhaust to atmosphere. This is provided since, under the conditions stated, the openings 94 in the cup, 82 in the cylindrical extension of the piston, and openings 44 in the tube 22 are aligned so that the air from the interior of the cup may be exhausted through these openings into the annular clearance 48 which, at its lower end, communicates with the atmosphere. It will be noted that this flow of air is provided without in any way interfering with the maintenance of pressure beneath the piston as is required to keep the clamp open.

Pressure below the piston is maintained during the knitting of the welt and until transfer of the stitches from the elements 14 is effected in conventional fashion.

After this has occurred, the gate 50 is rotated to a position opening to a slight extent the passage 36 through which the stocking is ultimately ejected. This will provide sufiicient drop in pressure within the tube below the piston to cause the spring 84 to move the piston downwardly and with it the clamp 60 to engage the portion of the welt between this clamp and the cup 90. This action may be immediately followed by release of the stem of valve 102 to cut off the air supply to the connection and to vent this connection to the atmosphere. Pressure in the tube 22 immediately drops to atmospheric pressure so that the grab assembly is free to move downwardly. The sequence of steps just decsribed is desirable to prevent any rapid drop which may cause the clamp to miss proper engagement with the welt.

Knitting then proceeds in conventional fashion for the formation of the leg, heel, instep, toe and loopers rounds of the stocking. During this knitting the weight of the grab assembly provides tension on the stocking.

The stocking is free to rotate and oscillate by reason of the fact that both the clamp and the cup are mounted on ball bearings so as to be readily revolved with little twisting of the stocking. The piston by reason of its close fit in tube 22 may not freely revolve because of friction; but this has no effect on the free rotation of the cup and clamp.

When the loopers rounds are completed and the stocking is pressed off the needles, the grab assembly with the stocking still secured therein will drop to the bottom of the tube into engagement with the member 24, the plastic button 75 cushioning the impact. The tube is made sufiiciently long so that any stocking which the machine may be called upon to produce will be completed and pressed oft before the grab assembly reaches the lower extremity of its movement.

Following what was last described, the top of the clamp occupies the position illustrated in FIGURE 2 so that the stocking is at the level of the opening 36. The gate 50 is now moved to open position providing a free outlet through the opening 36. At this time the latch 118 is brought into alignment with the slot 126 in the tube 22 so that it may move inwardly under the action of spring 122 to enter the annular groove 124 in the cup 90. This will prevent the cup from moving upwardly. Air pressure is now again applied below the piston by operation of valve 102 with the result that the clamp moves upwardly away from the upper edge of the cup releasing the stocking. Simultaneously with this or immediately afterwards the valve 65 is opened to provide a blast of air through the opening 30 to drive the stocking outwardly through the opening 36 and the aligned opening of the gate into the usual delivery tube which is not shown. Finally the cycle of operation is terminated by cutting off the supply of air to the connection 100 by release of the stem 106 of valve 102. The gate 50 is then moved to its closed position either at this time or after a new stocking has been started. The cycle of operation is then repeated for the new stocking.

It will be noted from the above that the operation is almost entirely under pneumatic control save for the simple mechanical operation of the valve and of the gate from the main cam drum through entirely conventional connections. Mechanical complications are thus avoided. Further, the grab assembly has a minimum vertical extent eliminating the necessity for providing special height of the machine.

It will be evident that various details of construction and operation may be changed Without departing from the invention as defined in the following claims.

What is claimed is:

1. A circular knitting machine comprising a hollow needle cylinder, needles mounted in said cylinder, elements cooperating with said needles for the production of fabric, an elongated cylinder concentric with and extending below the needle cylinder and located to receive produced fabric, a piston slidable in said elongated cylinder, fabric clamping means carried by said piston and comprising a cup having an upper edge closely fitting the interior of the top of said elongated cylinder and a clamp having a portion arranged to engage produced fabric and clamp it to said edge, means supplying air to raise the piston and clamping means to the upper end of said elongated cylinder adjacent to the needles, means effecting opening of the clamping means when the piston and clamping means are so raised, and means for directing air against produced fabric and therethrough into the upper portion of said cup to drive the fabric inside said edge and into said cup, said cup and said elongated cylinder having openings which are aligned and located above the piston and adjacent to the bottom of the cup when the piston and clamping means are so raised to provide escape from the bottom of the cup of the air directed against the produced fabric, said piston providing a barrier between the air escaping from the cup and the high pressure air below the piston.

2. A circular knitting machine according to claim 1 in which the piston and clamp are connected to each other and movable relatively to the cup, and in which a spring urges the clamping means towards fabric engaging position and a stop is provided to arrest upward movement of the cup so that further movement of the piston under the action of air pressure effects opening of the clamping means when the upward movement of the cup is arrested.

3. A circular knitting machine according to claim 2 in Which a latch is provided at the lower end of said elongated cylinder to arrest movement of said cup so that application of air to the piston by said air supplying means will elfect opening of the clamping means to release fabric held thereby.

References Cited by the Examiner UNITED STATES PATENTS 2,230,974 2/1941 Gagne a 66149 2,625,026 1/1953 Lawson 66157 2,709,352 5/1955 Lawson 66149 2,729,082 1/1956 TeW 66149 2,795,943 1/1957 Moretta 66149 3,036,449 5/1962 St. Pierre et a1. 66150 3,071,948 1/1963 Comas 66149 ROBERT R. MACKEY, Primary Examiner. RUSSELL C. MADER, Examiner.

W. C. REYNOLDS, Assistant Examiner. 

1. A CIRCULAR KNITTING MACHINE COMPRISING A HOLLOW NEEDLE CYLINDER, NEEDLES MOUNTED IN SAID CYLINDER, ELEMENTS COOPERATING WITH SAID NEEDLES FOR THE PRODUCTION OF FABRIC, AN ELONGATED CYLINDER CONCENTRIC WITH AND EXTENDING BELOW THE NEEDLE CYLINDER AND LOCATED TO RECEIVE PRODUCED FABRIC, A PISTON SLIDABLE IN SAID ELONGATED CYLINDER, FABRIC CLAMPING MEANS CARRIED BY SAID PISTON AND COMPRISING A CUP HAVING AN UPPER EDGE CLOSELY FITTING THE INTERIOR OF THE TOP OF SAID ELONGATED CYLINDER AND A CLAMP HAVING A PORTION ARRANGED TO ENGAGE PRODUCED FABRIC AND CLAMP IT TO SAID EDGE, MEANS SUPPLYING AIR TO RAISE THE PISTON AND CLAMPING MEANS TO THE UPPER END OF SAID ELONGATED CYLINDER ADJACENT TO THE NEEDLES, MEANS EFFECTING OPENING OF THE CLAMPING MEANS WHEN THE PISTON AND CLAMPING MEANS ARE SO RAISED, AND MEANS FOR DIRECTING AIR AGAINST PRODUCED FABRIC AND THERETHROUGH INTO THE UPPER PORTION OF SAID CUP TO DRIVE THE FABRIC INSIDE SAID EDGE AND INTO SAID CUP, SAID CUP AND SAID ELONGATED CYLINDER HAVING OPENINGS WHICH ARE ALIGNED AND LOCATED ABOVE THE PISTON AND ADJACENT TO THE BOTTOM OF THE CUP WHEN THE PISTON AND CLAMPING MEANS ARE SO RAISED TO PROVIDE ESCAPE FROM THE BOTTOM OF THE CUP OF THE AIR DIRECTED AGAINST THE PRODUCED FABRIC, SAID PISTON PROVIDING A BARRIER BETWEEN THE AIR ESCAPING FROM THE CUP AND THE HIGH PRESSURE AIR BELOW THE PISTON. 